Hi A., Your little sweetheart, is testing you to the limits, but this behavior is only perfectly normal for the child who is allowed to behave in this manner, I know you are using time out, and you are right when you said it doesn't work. This is a difference between punishment and discipline. Punishment is an on the spot action for unacceptable behavior, where as discipline is an action to modify the behavior, you said you are looking for positive discipline that is effected, but any discipline that's effective is positive. When our 3 kids (now grown) were growing up we didn't really do down out spanking, but we did do swats two, two swats, now did we make the swats count, you better believe it, my husband was more of the disciplinary, and if he ever had to swat our kids for the same thing more than once, it was rare. With our children we started discipline early so we had to tantrums, we had no screaming, our first son slapped my husband across the face once at 1year and 10 months, my husband gave him 2 good swats, and he never did it again, that son is 25 now and he tributes the man he is today, to the discipline and upbringing we did, all 3 of our children tribute who they are to our discipline and up bringing. We picked our battles, and with somethings it was a punishment, but for others it was discipline. Sweetie a 21 month old no matter how bad the behavior, do know it's bad unless there are consiquiences for it. And discipline has to have an impact on the child to where the child thinks to him/her self, I'm not doing that again, if you are disciplining a child for the same thing every day several times a day, then it's not effective or positive discipline. I've been a mom for 25 years, and a daycare provider for 12, I don't know everything, but i do know what works and what doesn't in most cases.I came to the conclusion when I was younger before having children that the term "Terrible Twos" was just away to explain away bad behavior. But she's still little, she is moldeble, just be patient, but firm, and once she learns you and your husband in in control her behavior will start to change, your 7 year old needs to be able to just walk away, when your 21 month old screems at her, and you probably wont like this, but if she hits your 7 year old, she needs to hit her back, not hard, but to let her know that she can no longer get away with hitting. I hope this helps. I am old school, but you know what sweetie, all the behavior issues that i have read through mamasource today, the majority of parents in my time did not have any of these issues, because in our day, discipline was not absent, and In don't mean time out, I mean discipline. J. L.